Ngu^nThiMayvaO/g Tgp chi KHOA HQC & CONG NGHE 126(12) 181 187 TAI BIEN T R i r O T L d D A T Of TINH CAO BANG NGUYEN NHAN VA GlAl P H A P PHONG T R A N H , G I A M NHE Nguyin Thj Mdy''''*, Trin Viet Khan[.]
Trang 1TAI BIEN T R i r O T L d D A T Of T I N H C A O BANG NGUYEN NHAN
VA G l A l P H A P P H O N G T R A N H , G I A M N H E
Nguyin Thj Mdy'*, Trin Viet Khanh\ Ta Thj-Tho'
'Trudng Dai hgc Suphgm - DH Thdi Nguyen ^Dgi hoc That Nguyen
T6M TAT
Trong miy th|p ky gan day, trugt Id dit Id mft dgng tai bien ty nhiSn xay ra tuong ddi ph<> biin d viing doi niii Viet Nam Dac bift dgc theo cdc tuyen duong mdi dugc xay dyng, cac tuylii dudng
dang dugc md r^ng ho^c nin thing Cdc khu dan cu tap trung dudi chdn sudn d6c va dpc cdc bd
khu dan dnh hudng tdi sinh hogt cung nhu ddi sing vgt chat, tinh than cua bd con noi day
Tfr khda: tai biin, trtrgt Id ddt, hiin trgng, hdu qud, nguyen nhdn gidi phdp
MO DAU
Cao Bang Id mgt tinh mien nui bien gidi
thufc Ddng Bic Bg Dia hinh chu yeu ggm
cdc nui trung binh va nui thap cd dg cao tu
300 den gin 2000 m, bj phan di, chia cdt vd
chju tdc dgng mgnh me bdi tai bifn trugt Id
dat Hang nam, vdo miia mua, trugt Id dat xay
ra khd phd bien tren nhiing khu vyc cd dia
hinh ddc Trugt Id da phd huy va lam hu hai
nhilu ngdi nhd dan, cdc cdng trinh cdng cgng
va thyc su khdng chi thift hgi vf kinh tf md
con gdy hoang mang lo sg trong nhan dan Dl
gidm thieu tdt nhat cac tai bien nay, chffng tdi
tifn hdnh nghifn cmi tim hilu vl nguyen nhan,
CO chf xuat hifn, dy bao, khoanh vung boat
dgng tai biin va tu dd d l xuit nhung giai phap
xu ly kip thdi vd phdng tranh cd hifu qua
K H A I N I E M V E T R U O T LCJ
Trugt Id Id mgt dang tai bifn dja chit phd
bifn d cac tinh miln ntii, hien nay cd nhifu
dinh nghTa vf trugt Id khde nhau, song cung
dfu thdng nhit dinh nghTa ve trugt Id nhu
sau: " Tru0 l& la qud trinh chuyen dgng cua
dat dd ve phia dir&l sudn doc dual dnh huong
ciia trgng luc." Neu theo quan difm vl dia
mgo thi trugt Id thyc chat la qua trinh sudn dudi
tac dpng cua nhieu yfu to khde nhau: do ddc
sudn, nudc chdy tren mat, nudc ngim, tinh chit
CO ly Clia dit da, hogt dgng tan kiln tgo
Cd nhilu each phdn logi trugt Id Tuy nhien,
chung tdi cho ring sy phan logi trugt Id theo
' Tel 01278 262828
kieu chuyfn ddng theo "ngudn gdc"ciia cCia cdc giao su dia chdt, trudng dai hgc Michigan ciia
My don gidn vd df hifu Theo each phan loai nay trugt Id bao gdm chu yfu cdc loai sau;
Trufft: la cac vat lieu dat da dugc chuyfn
ddng tff tff dudi tac ddng cffa trong lyc xudng dudi chdn sudn, cac vat lifu nhieu khi cdn giff nguyen cdu tnic (mat ldp) ban dau trudc khi xay ra trugt Trong trudng hgp khdi trugt theo mgt ddng keo dai vdi chifu ddi ldn gap nhieu
lan so vdi be rgng thi dugc ggi la trugt dong
Kieu trugt ddng ndy thudng xay ra dgc theo cdc sudi nhd va di kem vdi nd la lii bun da
Phan tfch chi tift hon vf hien frgng cua cac khdi trugt chung ta cd thf cdn phdn biet dugc mdt sd phy kieu trugt khde:
+ Trugt theo vd phong hod, tffc la khoi trugt
cd mgt trugt (guong trugt) ndm trong vd phong hoa hoac mgt tifp xuc giffa vd-phong hoa va mat da gdc
+ Trugt theo mgt ldp la khdi trugt cd mat trugt chinh theo mgt phan Idp cua dat da hogc theo mdt mat nut ciia dd Kilu truot nay thudng hay xdy ra khi mat ldp, mat khe nfft cua dat dd tning vdi hudng sudn
Trirgt chdy: la cac vat lifu dit da chuyen
dgng tu bdc dia hinh cao theo sudn ddc xudng bgc dia hinh thip hon theo mgt ddng rdi, vat lifu dugc sip xep hdn ddn, phd buy hoan toan cau true ban diu Qua trinh ndy xay ra thudng
d noi cd vdt lifu cd kich thudc hdn dgn, kem theo giffa cdc khoi dd cffng la cac vat lifu hat min set ngdm nudc hoac biin nhao
Trang 2Bd Id: la hifn tugng cdc vat lieu chuyen dgng
gin nhu roi ty do tff tren phin dia binh cao
xudng phfa dia binh thip va bang Dilu kifn
xdy ra dd Id la bf mat nghifng cffa mgt
trugt ldn hon mat nghieng cua sudn dia
hinh, hodc it nhdt sudn dia hinh cd dd ddc
gan thdng dung
Hdn hop: la hien tugng dien ra cua hai qua
trinh trugt va dd Id Qua trinh xay ra d noi cd
chiiu ddi sudn ldn, cd sy thay ddi dot ngdt ve
dd ddc sudn
Thyc tf, d nhieu noi, rat hilm khi cd thi quan
sdt thiy cac khdi trugt xay ra rifng biet ma
phan ldn la kit hgp cd hai qua hinh tren Kft
qua dilu tra khao sdt hien tugng trugt Id d
Cao Bdng cung phin Idn gap trudng hgp nay
va dugc ggi chung Id trufft Id hdn hgp
PHU'ONG P H A P N G H I E N CUXJ
D I giai quyft cac nhifm vu vd yeu cau thyc te
chung tdi dd su dyng cdc phuong phap nghifn
cun va khdo sat sau:
1) Difu tra khao sat thyc dia
2) Thu thgp xff li tai lifu
3) Phan tich tdng hgp cac ket qud khao sdt de
danh gid nguyfn nhdn, co che xuat hien va
phgm vi anh hudng cua cac tai biin, kiln nghi
giai phap phdng tranh
KET QUA N G H I E N CUTJ
Nguyin nhdn vd nhdn to dnh hu&ng
Nhu da biet, nguyen nhdn gay trugt cd the
hogc la do do ben cua dat da bj giam di, hogc
la do trgng thai ung suit d sudn ddc bi thay
ddi, hoac do cd hai nguyfn nhdn hfn lam cho
difu kifn cdn bang ciia khdi ddt dd d sudn doc
bj phd buy Cac yiu td anh hudng Id todn bg
nhiing yeu td ty nhifn va nhan tao cd tac dyng
hd trg cho qud trinh phd hogi sy can bang cua
khdi ddt da xdy ra dugc df dang Tropg nhffng
trudng hgp thudng gdp nhit cac yfu td nay
nay cd thf bao gdm cac yfu td ty nhien, nhu
dgc diem dja chat (dja ting, kiln tao, diit gay,
nfft ne, chi tifu co ly cua dit da, ddc diem
nudc dudi dat, cdc qud trinh va hifn tugng dia
chat dgng lyc cdng trinh ), cdc dilu kifn dja
ly ty nhien (dja hinh, dja mgo, khf tugng, thiiy van ), cac yfu td thdi gian va cac yfu to nhdn sinh (pha riing, cdc logi ngogi lyc do con ngudi tac dyng Ifn sudn ddc, muc dd dung din cua phuong an thiet ke, cdng nghf va tifn
dg thi cdng bd ddc nhdn tao ) Anh hudng xau cua cac yeu td tren lam giam khd nang chong trugt cua khdi dat dd d sudn doc, thay ddi trgng thai ffng sudt hong khdi dat da Cac yeu td dd kit hgp dan xen vdi nhau tgo nfn cac CO chl mit dn dinh sudn ddc khde nhau
Nhdn td dia hinh dia mgg
Cao Bdng la vung cd dia hinh phffc tgp vd da dgng dugc thf hifn tren ba mifn dja hinh chu yfu: Miln dia hinh Karst, miln dja hinh mii cao, mien dia hinh nui thdp thung liing Qua kit qua thdng kf cho thdy sd lucmg cdc diem trugt Id dat da ty If thugn vdi do cao vd dp ddc dia hinh Cd trfn 60% so dilm trugt Id phan bd d cac khu vyc cd do cao dia hinh tu
500 din 1000 m va do ddc sudn ldn hon 35° Trong cac don vi dia mgo khac nhau, dieu kifn dia hinh gay trugt Id cung khac nhau, theo kft qua nghien ciru cua df an trugt Id xay ra manh me nhdt d cac thung lung xam thyc, tilp theo Id cdc vung nui cao, mii trung binh vd thdp nhat la d cdc nui va cao nguyen
da vdi, cdc trung cd ngudn gdc khde nhau
Nhdn to dia chdt
Ddc dilm thgch hgc vd vd phong hod ciia viing la nguyfn nhan dja chat chinh lien quan dfn tifm nang phat sinh trugt Id dat dd va chffng cd moi lien quan khd chdt che vdi nhau Ket qua khdo sat cho thiy cac thdnh tao trim tich luc nguyfn tudi Paleozoi va Mesozoi trong vung phdn bd trfn difn rdng, trong dd san pham phong hoa tff ddt da cd thanh phin cat kit, thach anh, da phifn set, da philn set vdi tudi Paleozoi (thugc cdc hf ting Thin Sa, Luge Khieu, Mia Le, Nd Qudn va Tdc Tdt) df tham gia vdo qua trinh ttWttt id dit Trong thyc te, thdnh phin khodng ,v,at ciia nhdm dd ndy Id set sericit bj nen ep, phan ldp mdng, mat phan ldp nhieu noi trung vdi mgt doc dja hinh, vd phong boa cua chung chu yiu
Trang 3Id vyn thd nen khd nang frugt Id dit da rit cao
va xuit hien dgc cac myf n tinh If 206, 207,
208,211 vd dogn nam deo Gid trfn Qudc lg 3
Nhdn Id dg ddc sican
Cao Bang la vffng cd dia hinh phffc tap, bj
phdn cit mgnh Phin ldn dien tfch cua Cao
Bdng la cac mii da vdi tao thdnh cdc day niif
hogc tiing khdi nui ddc lap phan bd chu yeu d
phia ddng Nhung vung dia hinh thodi, vdi df
doc <15 chi gap d cdc thung lung dgc theo
cac he thdng sdng chfnh vd chiim mdt difn
tich khdng Idn d tdy nam Bdo Lam, vung ddi
nui thip cua Hod An, Thgch An va Phuc Hoa,
thi xa Cao Bdng Ngodi cdc vung nui dd vdi
va cdc vung cd dia hinh thodi vdi do ddc <15^
thi hdu hft phdn lanh thd cdn lai la vung cd dg
ddc d cap 25- 35° vd >35'*, dd la cac vung Bag
Lgc, Nguyen Binh, Thach An, tiy nam Bdo
Lam va mgt phin ianh tho phia ddng Cao
Bdng Trfn cdc khu vuc vdi do ddc sudn Idn
hon 25" trugt Id thudng xdy ra lien tyc, mgnh
me trong nhifu ndm
Nhdn to vd phong hoa
Do tac ddng cua qud trinh phong hod cdc dit
dd bi phd huy, dap vd, mdi lien ket co hgc bj
phd vd, cdc thdnh tao dja chit ban dau tu chd
rat cffng frd nen mem bd Dua theo cac dgc
diem thach hgc, d Cao Bdng phdt triln chu
yiu 2 kieu vd phong hod: Saprolit- dang
phong hod vgt ly ldm cho dd gdc bj nut v9 tgo
thdnh vyn thd va vd phong boa set- set loang
lo Hai kilu vd nay hiu nhu cffng song song
ton tgi va phat trien rit rfng rdi trfn cac cdc
dang dja hinh Ngoai hai kilu vd phong boa
ca bdn trfn, d Cao Bdng rat phat trifn logi vd
phong hod terrarossa hinh thanh trfn cac cao
nguyen dd vdi hogc cdc cdnh ddng, thung
lung karst d Hd Qudng, Thdng Ndng, Qudng
Uyfn, Trung Khdnh, Ha Lang,
Do dja hinh bj phdn cdt manh va do cao bien
doi nhifu, nen trfn lanh tho Cao Bang'bl diy
cffa vd phong hod cung thay doi rdt dgt nggt
Kft qua khdo sdt chi tiet d khU vuc xa Chf
Vifn cho thiy d nhimg vung dja hinh cao, dg
d6c Idn vd phong hod thudng mdng hon, ldp
thd nhuong cung rat mdng, song da gdc Iai bj nfft ne manh nen trugt Id phat triln rit rim rg, thim chf cd noi trugt sau vao trong ting da goc chua bj phong hod Cd nhiing vCing mac
du vd phong hod rat day song do mffc dg phong hod khdng ddng nhat ddn dfn dg gin ket kem nen kem on dinh vl mat co hgc, khi
cd cdc cdng trinh Iam dudng cdt qua da ldm mat cin bdng trgn£ lyc ddn den tru^t Id
Nhdn td ddi dgng lire dut gay
Trfn lanh thd Cao Bdng, cac ddi dfft gay TKT
cd the chia Idm 3 nhdm dua theo quy md va vai trd cua chung trong qua trinh hinh thanh
va phat trifn cac khoi ciu tnic TKT: + Nhdm cac diit gay phan chia ddi cdu tnic: Ddi dut gay Cao Bdng- Lgng San Mgt mat, ddi diit gay nay ddng vai trd phdn each ddi ciu true TKT Ddng Cao Bdng vdi ddi ciu trffc TKT Tdy Cao Bdng, mat khde chfnh hi hogt dgng cua nd ma hinh thanh trung keo tdch Cao Bang trong Kainozoi mugn + Nhdm cdc ddi dirt gay phan chia cdc khdi kien tnic trong-ddi cau true d Cao Bang chff yiu cd phuong Tay bdc- Ddng nam; Ddi dut gay Sdng Nang, Bdo Lac- Nguyfn Binh, Thdng Ndng- Tai Hd Sin va Sdng Bac Vgng
1 Cdc ddi dirt gay nay ddng vai trd chu dgo trong hinh thanh va phat trien cdc khdi cdu tnic TKT cffa vung
+ Nhdm cdc ddi dut gay xuyfn cat khdi cdu true va hinh thdnh cdc ciu true bgc thip hon, gdm cdc ddi dut gay phucmg Tay bac- Ddng nam: Pic Mifu- Nd Liim, Sdng Quay Son 1, Sdng Bdc Vgng 2, Pd Huy- Pdc Phiec; va cac ddi dirt gay phuong ddng bac- tay nam: Gidc Mg- Sdc Chdng, Nd Giang- Pdc Thdy, Ma Phuc- Gd Chang
Nhdn to lugng mua trung binh ndm
Che dg mua d Cao Bang lien quan chat che vdi chf do gid mua khu vyc va difu kifn dja hinh Lugng mua trung binh ndm cua tinh Cao Bdng bien ddi trong phgm vi tff khoang 1.30Dmm dfn 1.800mm Vung mua nhifu nhdt tinh la vung nui cao ddn gid am Nguyfn
Trang 4Binh, TTnh Tffc, Ddng Mu, Lung Pan Lugng
mua nam d nhihig vimg nay ldn trfn
1.700mm Vung mua tuong ddi la vung
Trimg Khanh, Na Vuong cd lugng mua nam
trfn 1.600mm Vung khd hgn va it mua nhdt
Id thung liing Bao Lac; nguyfn do la dia hinh
khuat gid am Lugng mua nam d day chi xdp
xi 1.300mm Nhihig thung lung khuat gid nhu
Thgch An, Cao Bang cung cd lugng mua nhd
hon 1.400mm
Mua la nhdn td rat quan trgng trong viec phat
sinh gdy trugt Id Mac du mgt sd noi cd lugng
mua trung binh nam thdp nhung lugng mua
lgi tgp trung vao mgt vai thang miia mua Su
tap trung lugng mua trong thdi gian ngan se
tac ddng manh gay trugt Id Lugng mua ngay
ldn nhat da xuat hien tgi Tram Cao Bang la
86,6mm (ngay 25/5/2001), hong khi tgi Trgm
Nguyen Binh la 174,5mm (ngay 5/10/2000)
Nhdn to mat do song suoi
Cao Bdng cd he thdng sdng sudi khd day, todn
tinh cd khoang 1200 sdng, sudi cd chifu dai
tff 2km trd len vdi tdng chieu dai sdng sudi la
3.175km Vdi ddc diem dja hinh cd do chia
cat mgnh, hudng cdc day niii chu yfu la
TB-DN nen sdng suoi cung cd hudng chff yiu
theo hudng TB- DN Cac sdng sudi chinh
trong vung la: Sdng Bdng, Sdng Gdm, Sdng
Quay Son
Mgng Iudi sdng sudi cua Cao Bdng khd day
vdi mat do sdng sudi Id 0,41Ikm/km^ Rd
rang, khi mat do sdng sudi cao chiing td dja
hinh hi phan cat manh ma sy phan cdt dia
hinh Id phdn anh true tiep cua cdc van ddng
kien tgo tre Sy phdn cdt dja hinh tao khdng
gian trugt rit ldn, mat do trugt Id cung tap
trung cao vdo nhirng thung lung sdng suoi
Hogt dgng nhdn sinh
Nhting hoat dgng ciia con ngudi trong cudc
sdng hang ngdy ciing gdp phdn tac dgng tieu
cue dfn qua trinh phat sinh phdt triln tai bien
trugt Id dat Cdc hien tugng trugt Id cd thf la
kit qua tryc tilp hay gidn tilp lifn quan dfn
cdc hogt ddng ciia con ngudi
+ Cac hogt dgng xe nui Idm dudng, Idm tang toe do cua qua trinh sudn, tdng khd ndng lam mat on djnh sudn
+ Cac boat dfng lam tdng trgng tai trfn cac sudn ddc, tdng khd nang lam mdt dn dinh sudn, lam thay ddi che df thuy van trfn sudn vd do dd gay tdc ddng xdu den sy dn dinh cua sudn + Vifc chgt cay, phd rffng Idm tang kha nang xdi mdn dat va lam yeu di khd ndng giu dit cua cay, do do lam giam di kha ndng boc -thodt hoi nudc
Hien trang trugt la a Cao Bang
TBTLD Id loai hinh tai bien dja chat ph6 biin nhdt d Cao Bang, xay ra thudng xuyfn va d nhifu khu vyc vd 4trgc phan chia thanh 3 vung ldn: cdc huyfn mien ddng, cac huyfn miln tdy, khu vyc trung tam thj xa Cao Bdng
Tai biin tru01& ddt & huy^n mien tdy
- Difm trugt Id Idn nhit d huyen mifn tay
tinh Cao Bdng phai ndi den dau tifn Id tgi ban
Na Lum, xd Thdi Hgc, huyfn Bao Lam xay ra vdo hdi 12 gid trua ngay 18/9/1995 trong dilu kifn thdi tilt nang khd Nfft dat xay ra hong phgm vi tuong doi rgng, vdi chieu rpng khoang 300m, dgc theo thung liing sdng cd dg cao tucmg ddi khoang 500m Cung trugt chgy theo phucmg d kinh tuyen dai khoang 70-80m, doc khoang 70- 80° Thdn trugt cit sau vao sudn nui tdi 70- 80m va trugt khdi vi tri ban ddu tao nfn vdch trugt vdi thfm trugt chfnh cao khoang 40m Vdch trugt nghifng
vf phia tiy vdi goc ddc tdi 80", khdi frugt phdt trifn trong ting dd bien chat he ting
Tdng Bd (O- S tb) vdi thdnh phin chff yiu la
da phifn thgch anh- xerixit, xen kep cac ldp mdng quarzit va cac tap phun trao thanh phan axit Theo tfnh todn so bg, khoi lugng dat da
bi di chuyen xuong dudi khoang 500.000m^ Mdt lugng Idn dat da di chuyen xudng dudi tgo nen ddng Iu bim dd khdng Id lip ddy ddng sudi d phia dudi chan sudn nffi
- Vdo thang 7/1998, tgi ban Khieu, xa Son Lp, huyfn Bao Lgc mgt vft nfft ddi cit qua mgt loat cdc ngdi nha cua cu ddn ngudi dan tgc
Trang 5Sdn Chi Khe nfft cd dang ngodn ngheo kifu
trugt cdt, chay theo phuang TB- DN, dai
khodng 800- 1.000m, rgng chung 7- 12cm
Bifn do djch chuyin thing dffng quan sdt
dugc khoang 3cm Vlt nut cdt qua nin sin,
nen nha ldm nut tudng nhd cua cu ddn thudc
ban Khieu keo dai din tan sdng Ndng Khe
nfft nay da gdp phan tao nen cung trugt keo
dai theo phuong a kinh tuyen va khdi trugt
nay da trugt khdi vi trf ban dau khodng 2- 3m
vf phfa sdng Ndng
Tai bien trugt l& ddt a huyen miin dong
Trgn lu quet kem theo trugt Id d Trung
Khanh- Hg Lang xdy ra dfm 7/6/2001 cd the
coi la mgt trong nhung su cd mdi trudng dja
chat Idn nhit d vffng DB frong vdng 10 nam
trd Igi day Difn trugt !d vd chju anh hudng lii
quet rat rf ng bao trum hau het viing DB Cao
Bdng, tren dja ban cua hang chyc xa, nhu:
Phong Chiu, Chi Vifn, Cao Thdng, Dam
Thuy (Trimg Khanh); Minh Long, Ddng
Loan, Thang Lgi, Dffc Quang, Kim Loan, Ly
Qudc (Hg Lang) Tu cudi thdng 5, diu thdng
6 nam 2001 tgi vffng nffi dat thdp, lugng mua
ldn bit thudng, tgi Trgm Khf tugng Trung
Khdnh (cdch noi xdy ra sy cd gdn 20km)
trong 15 ngdy da do dugc tren 500mm Rieng
trong dfm xdy ra sy cd da cd mua ldn trong
khu vyc (tdi 100mm) Den 11 h dem, ngudi
ddn nghe thdy nhifu tieng ddng ldn do dat da
bj dd Id vd cudn trdi, den sdng 8/6/2001 khi
mua ngdt, toan doi nffi dat d 9 xa kl trfn bj
sgt Id nghiem trgng, nudc dang diy cac con
sudi nhd va cuon trdi theo rat nhifu dat da,
cdy cdi, vui lip tit cd difn tfch canh tdc d cac
bd sudi, mgt sd noi cdn cudn trdi ca nhd cua
Cung vdi lu quet, trugt Id cung xay ra trfn
quy md rgng lam dd nhieu nha cffa Cdc canh
dong nhd cffa cac sudi deu bj dit cat vui lip,
cd noi bi vui siu dfn hdng met Nhieu dien
tfch hdng nam sau chua khdi phyc dugc
Nhifu dogn dudng tinh lg, dudng giao thdng
lien huyen, lien xa bj sat Id, hang tt-am mft
dudng, ciu cdng ndm tren con dudng di ciia
ddng lii hi phd buy, nhifu muong, phai thuy
lgi bi pha buy hoan toan Tai trang tam viing
lu, hd chffa nudc cd nguy co de dog vd dgp, muong dan nudc hi pha huy hodn todn, nudc tff hd chdy ra mang theo mui hdi, gay khd chiu cho ngudi dan sinh sdng trong vung
- Hifn tugng trugt Id tren cac tuyfn Quang Uyen-Phyc Hoa, Phyc Hoa-Ddng Khe va Ddng Khf-Cao Bdng xdy ra khdng manh me nhu d cdc huyen Hg Lang, Trimg Khanh vf quy md khdng gian cung nhu thdi gian Tren tuyfn dudng Phyc Hod-Ddng Khe ciing ghi nhgn dugc 5 dilm trugt Id each thj trin huyen Ddng Khf khoang 6 km ve phia ddng, vdi kich thudc khdng ldn: dai khodng 30-50 m, rgng khodng 40-50 m Cac difm trugt Id cung xay ra trfn vd phong hod day cua dit da Paleozoi bj phong hod mgnh me Trfn tuyfn dudng QL-4, doan Ddng Khe-Cao Bdng ghi nhgn cdc difm trugt Id cd tan xuit cao hon hdn so vdi nhiing tuyfn trfn Tuy nhien, cac khdi trugt cd quy md nhd nfn mffc do dnh hudng cung thdp hon
Tai biin trugt lo ddt & khu vuc trung tdm thi
xd Cao Bdng
Diem trugt Id xay ra tren sudn nui phfa phai sudi Clin each thj xa Cao Bdng khoang 1km
ve phia Ma Phyc Vj tri trugt Id nim tren sudn phia ddng nam cua ddi nffi cd do cao 400m, cd sudn khd ddc 35, vd phong hda thay ddi tff 2-15m, tai vj tri khdi trugt vd phong hda day 15m vdi thanh phin chu yfu la cat, cat pha set xen lan nhieu manh ddn Vd phong hda dugc thanh tao tff dd xdm nhap bazo va sieu bazo Sudn cd dgng thing vdi chifu dai sudn gin 500m keo dai tu dinh nui xuong tan dfn chin cffa day nui ndy Mgt sudn bj hf thdng cac khe suoi nhd cat xe tao nen cdc ranh cung keo thdng xudng chin nffi Dudi chan nui la sudi Cffn thudc mgt nhdnh cua sdng Bdng Giang, ldng sudi khd ddc vd tao nhieu bgc nhd (cac thac nudc) hai ben sudi gan nhu khdng cd cdc thanh tao thfm ddi chd chi Id cac bai boi nhd Theo ban dd tan kifn tao, thi tal ddy (vi tri trugt Id) la noi giao nhau cffa hai hf thdng dfft gay hogt dgng phuang
Trang 6tay bdc - ddng nam va bdc, ddng bac Vi vgy
trfn sudt mgt doan dai gin 20km da bj vd vun
mgnh me
KET LUAN VA KIEN NGHI
Qua kit qud nghifn cffu danh gia vai trd cua
cac yfu td phdt sinh, phat trien tai bifn trugt
Id dit, ciing nhu quy md vd mffc do dnh
hudng cua chung d Cao Bdng, chffng tdi di
den mgt sd kit lugn nhu sau:
Trfn lanh did Cao Bdng hgi ty nhifu yfu td
phdt sinh - phdt trien tai bifn dja chdt, ddc
bift la trugt Id dit do:
- Vifc phdt trifn rgng rai cdc thanh tgo tram
tich luc nguyen bj nen ep, dap nat do cdc dnh
hudng cua cdc boat dgng kiln tao cd vd trf
trfn Idnh thd
- Vd phong hoa phat trifn rit rgng rai, vdi df
diy ldn, lam tang khd ndng trugt Id cffa dat dd
trong vung
- Vdi Idnh thd cd dja hinh phdn cdt manh difn
tich dit cd dd ddc ldn, la mdi trudng thuan lgi
cho cac loai tai bien dia chdt
- Mgng Iudi sdng sudi phat trifn trong cac
thanh tao lyc nguyfn, tgo thdnh cdc khe siu,
hep, sudn ddc ciing Id tdc nhan thuc day phdt
sinh - phat trien tai bifn trugt Id dit hong tlnh
- Cd bifu hien rd ret cffa cdc ddi sinh chan va
cac ddi dfft gay hogt dgng
Tit ca cac yiu td ty nhien kf tren da cho thay
lanh thd Cao Bing khdng phdi Id vffng on
dinh ddi vdi tai bifn trugt Id dit
Bang vifc tich hgp cac yen td tai bifn trugt Id
dat da xay dyng dugc bdn do nguy co tai biin
trugt Id ddt Theo do, cac khu vyc cd nguy co
xdy ra trugt Id cao nhu d Bdo Lac, Bao Lam,
Hg Lang, Trung Khanh va mgt sd vffng khde
Ddy la nhung khu vyc hoan todn ndm trung
vdi cdc ddi xung yfu cua vd Trai Dit (ddi anh
hudng dgng luc dfft gay va cac ddi cd tinh
nang dia chan tuong ddi cao)
De phdng tranh, khde phuc vd gidm nhe tai
bifn hugt Id dit trfn dia ban tinh Cao Bing
chffng tdi xin de xuat mgt so giai phap sau:
Gidi phdp phi cdng trinh
Tuyen fruyen rdng rai cho ngudi ddn sy nguy hilm cua TB trugt Id dit va sgt Id nui
- Khdng cap phep va nghiem cam tuyft ddi vifc khai thac khodng sdn, cac cdng trinh xdy dyng cdc dilm ddn cu ndm trong phgm vi hanh lang bdo vf cua cdc tuyfn dudng
- Xay dyng he thdng bifn canh bdo cdch toi thifu la 500m d hai dau cdc doan dudng co nguy CO TB trugt Id cao df cac phuong tifn giao thdng dugc bift
- Quy hogch su dung dat; quan If xay dyng nha tai cac sudn ddi, ven sdng sudi, chin mii dgc dudng giao thdng
Gidi phdp cdng trinh
Trong thyc tifn, de ddi phd vdi TBTLD ngudi ta thudng sff dung nhieu nhdt cdc bien phdp sau day: Bifn phdp giam tdi, hgn chf tac hgi cua nudc mua, nudc mat, gia cd cdc khdi ddt da bdng ke chan va cdng trinh neo, cai tao tinh chdt cua dit da
Bien phdp gidm tdi
Trong bifn phap ndy, tien hdnh phdn bo lgi cac khdi dit da df ddm bdo do dn djnh ciia cac khdi trugt Khi dao cac taluy vdo sudn ddc, thf tich cac khdi dat dd d chdn khoi trugt ddng vai trd nhu khdi dd se mit di mdt phan hodc todn bg se dan den sy mat can bang
De thay ddi tuong quan img luc do, ta tifn hanh cat xen dat da d phdn chff dgng (khoi day) cffa khdi trugt hodc ddng thdi cit xen d phin chu dgng va ddp them thanh bf phan dp
d phan bi dgng (khdi dd) tai chan khoi trugt
Hgn che Idc hgl cUa nuoc mua nu&c mgt
Dudi tac dyng cua nudc mua, nudc mdt, dat
dd bi tdm udt, thay ddi trgng thai vdt ly va dg ben bj suy yeu, gay mat dn djnh bd doc Vifc hgn chl tdc hai cua nudc mua, nudc mat nen tap trung vao vifc difu tift cdc ddng mgt Cdng tdc difu tift ddng mat bao gom: San bing bf mat khdi trugt vd lanh thd ke can nd; Xdy dyng hf thong ddn nudc mat; Cdng tdc cai tgo dit bdng trdng cdy
Trang 7Su dung cdc bien phdp cdng trinh kien cd
Gia cd cdc khoi dit da bdng cdc giai phdp
cdng trinh nhu: xiy dyng tudng chdn, Iam he
thdng neo giff, xay dung cdc bf phdn dp d
chdn khdi trugt
Gidi phdp vexa hpi
Xd hgi hda cdng tac phdng, chdng vd gidm
nhe cdc TBTLD, huy ddng mgi nguon lyc cua
xa hgi, thyc hifn phuong cham nha nudc va
ngudi ddn cung idm nham giam thifu tdi da
tdc hai Clia TBTLD gdy ra
M& cdc lop boi duong ddo tgo cho ngu&l ddn
ve khd ndng tu iing pho v&i TB Gido due y
thiic bdo ve moi tru&ng cho ngu&l ddn,
nghiem dm cdc hdnh vi ddt nuang ldm rdy, dd
rdc & b& sdng suoi
Cdn cd nhffng chinh sach phff hgp, quan tdm
tdi ddi s6ng ngudi ddn, dac biet la ngudi ddn
sdng trong khu vyc thudng xuyen chiu dnh
hudng cua cac TBTLD
Thuc hifn cac chuang hinh tuong thin tuong
ai, quyfn gdp cffu trg cho cac vung xay ra
TB, nhanh chdng dn djnh cugc sdng, dam bao
sue khde cua ngudi dan, ddc bift la ngudi gia,
trf em vd ngudi tan tgt
TAI LIEU THAM K H A O
1 Trin Trong Hod (chii bign), (1998), Bdo cdo ting kit dl dn "Dilu tra ddnh gia hien frgng moi midng sinh thdi tinh Cao Bing Nghi6n ciiu cac giai phdp phyc hdi mdi trudng viing khai thac Cao Bing" Luu frff Sd CN-TTCN Cao Bdng 2.Trin Vilt Khanh, Nguyin Thi Mdy, (2009),
"Phan tich anh hudng cua dja hinh din tai biin
thiin nhien d tinh Thai NguySn" Tgp chi Khoa hgc va Cdng nghi Dgi hpc Thdi Nguyen
3 Ta Thj Tho , (2014), "Hifn trgng tai biin tmpt
Id dat d Cao Bdng Nguyen nhan va gidi phdp" Khda luSn t6t nghifp - Khoa Dia L^ - Trudng DHSP- DHTN
4 NgS Quang Todn (chii bien), (2000) Vd phong hod vd trdm tich Di lit Viet Nam
5 Nguyen Trpng YSm (chii biSn), 1999 Dieu tra, danh gia vd kiln nghi giai phdp xu ly SCMT miln niii Viet Nam (Khu Dong Bdc Viet Nam)-Bdo cdo t6ng kit dl tdi Luu frii UBDT MN vd Vien Dia chit-TT KHTN vd CNQG
6 Nguyen Trpng YSm (chii bien), (2002) Tdng kit hi thdng phdn vung du bdo vd di xudt cdc chu tniang, phuang phdp img phd hiru hiiu vdi cdc su cd mdi trudng (SCMT) a vUng ddng bdo ddn tgc vd mien nui nudc ta Bdo cdo tdng kit di idi-Lmi bu
UBDT MN vd Vifn Dja chit-TT KHTN vd CNQG
7 Lomtadje Dia chat cong trinh (3 tdp) (ban dich) Nxb DH vd THCN, Ha Npi, 1982 SUMMARY
LANDSLIDE DISASTER IN CAO BANG PROVINCE
CAUSES, SOLUTIONS AND MITIGATION
Nguyen Thi May'*, Tran Viet Khanh\ Ta Thi Tho'
College of Education — TNU Thai Nguyen University
In recent decades, landslide is one of natural disasters that happened quite common in mountainous regions in Vietnam In particular, along to the new road that just been built, all the the riverside, streamside As a consequence of landslide, it is not only covers all the roads, but also threatenning the residential areas as well as all the material and spirit of people' life here
Keywords: Disaster, landslide, status, consequences, causes, resolutions
Ngdy nhgn bdi: 15/9/2014; Ngdy phdn bien:03/10/2014; Ngdy difyit ddng: 25/10/2014
Phiin hiin khoa hoc: ThS Le Tien DSng - Dgi hgc Thdi Nguyen
'Tel :>1278262828